Angiography-Derived Microcirculatory Resistance in Detecting Microvascular Obstruction and Predicting Heart Failure After STEMI.

Background: Microvascular obstruction (MVO) is associated with heart failure (HF) following ST-segment-elevation myocardial infarction. Angiography-derived microcirculatory resistance (AMR), a wire- and adenosine-free measure, may facilitate early assessment of microvascular function post-primary percutaneous coronary intervention. This study aimed to evaluate the ability of AMR to detect MVO and its prognostic value for predicting HF in patients with ST-segment-elevation myocardial infarction post-primary percutaneous coronary intervention.

Methods: Patients with consecutive ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention with a cardiac magnetic resonance examination 2 to 7 days post-procedure between April 2016 and February 2023 were retrospectively reviewed. AMR was computed from coronary angiography. MVO was identified and quantified via cardiac magnetic resonance. The end point was new-onset HF during follow-up.

Results: Overall, 475 patients (aged 56.8±11.7 years; 399 men) were included. The area under the curve for AMR to detect MVO was 0.821 (95% CI, 0.782-0.859), with an optimal cutoff value of 2.7 mm Hg*s/cm. During a median follow-up of 37.3 months, 121 (25.5%) patients developed HF. AMR, whether as a continuous (per 0.5-mm Hg*s/cm increase; hazard ratio, 1.29 [95% CI, 1.10-1.52]; P=0.002) or categorical (AMR >2.7 mm Hg*s/cm; hazard ratio, 2.15 [95% CI, 1.43-3.22]; P<0.001) variable, was independently associated with HF after adjusting for traditional risk factors (age, symptom-to-balloon time, left anterior descending coronary artery, and ejection fraction) and late gadolinium enhancement-cardiac magnetic resonance parameters. AMR improved prognostication over traditional risk factors and late gadolinium enhancement-cardiac magnetic resonance parameters (net reclassification improvement, 0.533; P<0.001; integrative discrimination index, 0.023; P=0.005).

Conclusions: AMR showed good diagnostic performance in detecting MVO and was an independent and incremental predictor of HF in patients with ST-segment-elevation myocardial infarction post-primary percutaneous coronary intervention.